The invention concerns a process and an apparatus for the individual destruction of syringe needles by melting under the effect of a high-intensity electric current.
Worn syringe needles are dangerous waste and they constitute in particular a carrier for the transmission of viruses.
Apparatuses have already been proposed enabling worn syringe needles to be destroyed by melting under the effect of an electric arc. For example, WO-A-9300121 describes an incinerating device for needles comprising a pair of fixed electrodes for the progressive melting of the needle and clamping means enabling the residue of the needle to be sealed off at the end of the melting process. This device comprises a piston having an opening through which the needle is introduced. This opening cannot be traversed by the end piece carrying the needle, which has a larger diameter and which butts up against the piston at the end of the stroke. The piston is moved towards the electrodes until a micro-switch is actuated which activates an electric motor bringing about the clamping and plastic deformation of the residue of the needle between a pair of clamping jaws moved by the motor. The pair of clamping jaws may also be connected to an electric power source so as to enable an electric current to be applied between them, after a needle has been clamped, in order to seal the inside of the residual end of the needle. This complex and motorized device requires a high-capacity source of electricity and is heavy and bulky. It is not portable and has a life span limited by that of the electrodes. Moreover, it should be noted that since the clamping jaws are interposed between the piston and the electrodes, a residual length of the needle is still of necessity left at the extremity of the end piece of the needle or the syringe. Now, the inventors have found that this residual portion of the needle is as dangerous as, if not more so than a complete needle. In point of fact, it has been proved in practice that the small dimensions of this residual portion of the needle, far from reducing the risks of injury as could be expected, are in practice the cause of many accidents due to the fact that it is virtually invisible and has a deceptively inoffensive appearance.
Other similar devices have been proposed. In all cases however, a residual portion of the needle persists projecting from the extremity of the syringe end piece. This end portion can of course be cut into sections mechanically with the aid of a specific tool. Nevertheless, the problem still remains that the detached residual portion is not destroyed and is on the contrary sharp and potentially contaminated.
In addition, most of the devices previously proposed for destroying needles with the aid of an electric current are either bulky and not portable (in particular supplied by the electric mains), or are portable but are insufficiently independent or are not sufficiently effective to melt all needles. Moreover, all these apparatuses are extremely costly and have a limited life span due to the rapid wear of the electrodes, so that their use on a large scale for equipping personnel of the health occupations (nurses, physicians, dentists, hospital personnel, pharmacists, ambulance staff, first aid staff, fire fighting personnel, veterinary surgeons, etc.) or patients (diabetic patients etc.) cannot reasonably be considered.
In all the text, the expression xe2x80x9csyringe end piecexe2x80x9d designates, in a syringe comprising a syringe body carrying a needle, the end piece which carries the hollow tapered metal stem, the so called needle stem, forming the actual needle. The concept of xe2x80x9ca syringe end piecexe2x80x9d also encompasses in a similar manner the case where the needle is connected to a flexible tube acting as the syringe body (dialysis or sampling line, etc). More generally, in all the text, the term xe2x80x9csyringexe2x80x9d applies to any device for injecting liquids into, or sampling liquids from, a system to which a needle is associated, projecting from an end piece, the so-called syringe end piece. More often, the syringe end piece is formed of the female end piece of the needle carrying the needle stem, and which is connected to a mating male end piece of the syringe body. The syringe end piece has, at its end through which the needle stem emerges, a shoulder extending at least substantially radially outwards with respect to the needle stem and this end piece is slightly flared out towards the body of the syringe, the assembly between the male and female end pieces being generally of a conical type. This shoulder has a larger diameter than the needle stem.
The object of the invention is thus to overcome the above mentioned disadvantages by providing a process and an apparatus for the purpose of destruction by virtue of which each needle may be entirely destroyed without any dangerous waste or sharp residual portion projecting from the syringe end piece.
More particularly, the object of the invention is to provide a portable apparatus enabling needles to be entirely destroyed over all their axial length projecting from the syringe end pieces.
The object of the invention is more particularly to provide an apparatus which can be used with all needles, whatever their dimensions, in particular up to a diameter of the order of 1.2 mm.
The object of the invention is also to provide an apparatus having a considerable degree of autonomy which enables a large number of needles to be destroyed, in particular more than 80 needles with a diameter of 0.6 mm, between two recharges or two renewals of the electric power source.
The object of the invention is moreover to provide such an apparatus which is particularly simple and reliable, has a long life, is safe to use, and of which the cost is much lower, in particular three to five times lower, than that of previously known devices.
The object of the invention is moreover to provide a portable apparatus which is particularly ergonomic, easy and inexpensive to use and maintain, and which is light and small.
In all the text, the term xe2x80x9caxialxe2x80x9d and its derived terms designate a direction parallel to the axis of a needle to be destroyed, and the term xe2x80x9cradialxe2x80x9d and its derived terms designate a direction perpendicular to the axial direction. Moreover, the apparatus is assumed to be horizontal overall and the needle vertical overall with its free end downwards, although in practice this position is of course not compulsory. In addition, the expressions xe2x80x9cend portion of the needlexe2x80x9d and xe2x80x9cresidual end portion of the needlexe2x80x9d designate end portions of the tapered metal hollow stem forming the needle itself and therefore does not encompass the syringe end piece.
The invention thus concerns a process for the individual destruction of syringe needles by melting under the effect of a high-intensity electric current with the aid of electrodes connected via a power circuit to an electric power source, in which, in a first destruction step, the free end of a needle is applied in electrical contact with a lower electrode connected electrically to a first terminal of the electric power source, the outer surface of the needle is applied in electrical contact with a first upper electrode connected electrically to a second terminal of the electric power source which is distinct from the first terminal to which the lower electrode is connected, the distance between the electrical contact of the outer surface of the needle with the first upper electrode and the free end of the needle in electrical contact with the lower electrode being adapted so that the electric current established between the lower electrode and the first upper electrode via an end portion of the needle extending between these electrodes is capable of bringing about the melting of this end portion of the needle, and the needle is progressively melted by causing its outer surface in contact with the first upper electrode to slide axially as melting of the end portion progresses, wherein:
the first upper electrode has a free upper face against which a syringe end piece can butt up axially,
in a first destruction step, the needle is progressively melted by causing its outer surface in contact with the first upper electrode to slide axially until the syringe end piece carrying the needle arrives so as to butt up axially against the first upper electrode,
in a second subsequent destruction step, the second upper electrode is applied in electrical contact with the outer surface of the needle at least substantially radially opposite the first upper electrode, this second upper electrode being connected electrically to the same first terminal of the electric power source which is distinct from the second terminal to which the first upper electrode is connected, so that an electric current is established between the first upper electrode and the second upper electrode through the cross section of the needle flush with the syringe end piece butted up against the first upper electrode, whereby the residual end portion of the needle extending in projection from the syringe end piece is destroyed by electrical melting, flush with the end piece of this syringe, this residual end portion being destroyed by melting between the first upper electrode and the second upper electrode, and the melt residue being moreover detached from the syringe end piece which subsequently no longer presents any projecting asperities.
Advantageously and according to the invention, during the second destruction step, the first upper electrode and the second upper electrode are applied against the outer surface of the needle while exerting a radial pressure against them by manual action tending to bring them together while pinching the section of the needle.
Advantageously and according to the invention, the second upper electrode is applied with a radial pressure against the outer surface of the needle, whereas the outer surface of the needle is, on the other hand, butted up radially against the first upper electrode carried by a framework of the apparatus.
Thus, according to the process of the invention, during the subsequent second destruction step, the residual end portion of the needle stem, flush with the syringe end piece, is destroyed by electrical melting between the two upper electrodes. The melt residue is moreover detached from the syringe end piece which subsequently no longer presents sharp projecting asperities. On the contrary, the heat produced by melting the end portion by means of the two upper electrodes, tends to melt the extremity of the syringe end piece, at least partially, which has the effect of blocking it and presenting a particularly harmless surface appearance.
Since the residual end portion is destroyed by electrical melting, no complex motorized mechanical device for mechanical sectioning has to be provided, it being possible for the contact of the upper electrodes with this residual portion of the needle to be obtained by manual action. Nothing however will prevent means being provided which will make it possible to assist or facilitate this manual action, for example a spring providing a return action in the direction of separation, or on the other hand, of approach of the upper electrodes.
It should moreover be noted that the progressive melting of the needle at a high temperature (practically at a temperature greater than 1300xc2x0 C.) has the effect of bringing all the metal needle to a high temperature, including the portion of the needle which extends inside the syringe end piece. Destruction of micro-organisms and viruses is therefore obtained and hence sterilization of the syringe end piece.
The invention also extends to an apparatus for implementing the process according to the invention.
The invention also concerns an apparatus for the individual destruction of syringe needles by melting under the effect of a high-intensity electric current, comprising an electric power source and electrodes connected to the electric power source via a power circuit, these electrodes being adapted so that they can be placed in contact with a needle so as to establish between them, via a portion of the needle extending between these electrodes, an electric current which can bring about melting of this portion of the needle, these electrodes comprising:
a lower electrode adapted so as to receive the free end of a needle and to form therewith an electrical contact, this lower electrode being connected electrically to a first terminal of the electric power source,
a first upper electrode adapted so that it can be placed in electrical contact with the outer surface of the needle at an axial distance from the free end of the needle in contact with the lower electrode adapted so that the electric current established between the lower electrode and the first upper electrode via an end portion of the needle extending between these electrodes, is able to bring about melting of this end portion of the needle, this first upper electrode being connected electrically to a second terminal of the electric power source which is distinct from the first terminal to which the lower electrode is connected, wherein:
the first upper electrode has a free upper face against which a syringe end piece can butt up axially,
the electrodes include a second upper electrode adapted so that it can be placed in electrical contact with the outer surface of the needle at least substantially radially opposite the first upper electrode, this second upper electrode being connected electrically to the same first terminal of the electric power source which is distinct from the second terminal to which the first upper electrode is connected, so that an electric current can be established between the first upper electrode and the second upper electrode, through the section of the needle, whereby a residual end portion of the needle extending as a projection from the syringe end piece carrying the needle after the needle has been progressively melted between the first upper electrode and the lower electrode, can be destroyed by electrical melting between the first upper electrode and the second upper electrode, flush with the syringe end piece butted up against the first upper electrode, this residual end portion of the needle, the melt residue, being moreover detached from the syringe end piece which subsequently no longer presents any projecting asperities.
Advantageously and according to the invention, the free upper face of the first upper electrode against which the syringe end piece can butt up axially, presents a sharp straight edge against which the outer surface of the needle can be applied radially in order to establish tangential contact with this sharp straight edge.
Similarly, advantageously and according to the invention, the second upper electrode has a free upper face against which a syringe end piece can butt up axially, and a sharp straight edge which is defined by this free upper face and which may be applied radially against the outer surface of the needle in order to establish tangential contact with this sharp straight edge.
Advantageously and according to the invention, the first upper electrode and/or the second upper electrode is formed of an insert mounted in a detachable manner on a conducting electrode support.
Advantageously and according to the invention, the insert has several, in particular four, sharp straight edges and is mounted on the electrode support so as to make it possible to change the sharp straight edge designed to come into electrical contact with the outer surface of a needle. Advantageously, the insert has a square free upper face.
In addition, advantageously and according to the invention, the first upper electrode and/or the second upper electrode are/is made of tungsten carbide.
In addition, advantageously and according to the invention, the apparatus is characterized in that the first upper electrode is mounted fixed with respect to a frame of the apparatus and in that the second upper electrode is mounted so that it can be displaced radially in translation between a position away from the first upper electrode where only this first upper electrode is in contact with the outer surface of a needle and a position close to the first upper electrode where these two electrodes are in electrical contact with the outer surface of a needle.
Advantageously and according to the invention, the second upper electrode is mounted secured in translation to a push button adapted so that it can be actuated manually.
In addition, the invention also concerns an apparatus for the individual destruction of syringe needles by melting under the effect of a high-intensity electric current, comprising an electric power source and electrodes connected to the electric power source via a power circuit, these electrodes comprising a lower electrode adapted so as to receive the free end of a needle and to form therewith an electrical contact, this lower electrode being connected electrically to a terminal of the electric power source, and a first upper electrode adapted so that it can be placed in electrical contact with the outer surface of the needle, this first upper electrode being connected electrically to a terminal of the electric power source which is distinct from the terminal to which the lower electrode is connected, wherein:
the axial distance between the lower electrode and the electrical contact established between the outer surface of the needle and the first upper electrode is comprised between 3 mm and 5 mm, in particular of the order of 4 mm,
the electric power source comprises a voltage source delivering, between two terminals, a continuous voltage comprised between 1.8 V and 2.5 V,
the power circuit has a total internal resistance between the lower electrode and the first upper electrode via the electric power source, which is less than 50 mxcexa9 so that the apparatus may in particular be portable.
It has indeed been found that with these values it is possible to bring the portion of the needle comprised between the lower electrode and the first upper electrode to a high temperature (above 1300xc2x0 C.) and to melt this portion of the needle, and this with the most common commercial shapes and dimensions of needles. In particular, it is found that in spite of the low continuous voltage used (less than 2.5 V), an intensity greater than 60 A is achieved between the two electrodes.
Advantageously and according to the invention, the electric power source comprises at least one pair of cells or accumulators in series, each cell or accumulator delivering a voltage of the order of 1.2 V.
Advantageously and according to the invention, the electric power source comprises several, in particular three, pairs of cells or accumulators mounted in parallel, each cell or accumulator having a capacity above 1500 mAh, in particular of the order of 1800 mAh.
Preferably and according to the invention, the electric power source is formed of rechargeable cadmium-nickel accumulators.
In addition, it is important that the internal resistance of the power circuit is below 50 mxcexa9, and is as low as possible, in order to prevent any resistive losses and voltage drops before the electrodes are supplied. Advantageously and according to the invention, the apparatus is in addition characterized in that the power circuit includes at least one controlled electronic switching circuit which makes it possible to supply or isolate at least one of the electrodes from the corresponding terminal of the electric power source, and in that this controlled electronic switching circuit is adapted so as to have an internal resistance, in the closed state when the electrode is supplied, which is less than 15 mxcexa9, in particular of the order of 10 mxcexa9.
Advantageously and according to the invention, the controlled electrical switching circuit includes an MOS transistor, and the apparatus includes a voltage booster circuit enabling the transistor to be polarized from the electric power source. The voltage booster circuit enables the MOS transistor to be polarized at a voltage greater than the voltage delivered by the electric power source. As a voltage booster, it is possible to use for example, a voltage multiplier assembly, in particular of the Latour or Schenkel type consisting of diodes and capacitors.
In addition, the apparatus according to the invention advantageously includes a secondary electronic circuit making it possible in particular to control the operation of the apparatus (with a start and stop button, indicator lights, a charging circuit enabling the accumulators to be recharged from a transformer connected to the mains, a timer circuit making it possible to limit the duration of polarization of the electrodes while waiting for a needle to be destroyed, and a circuit controlling the electronic switching circuit (control and polarization of the switching of the MOS transistor applied to its grid etc)). Advantageously and according to the invention, this secondary electronic circuit includes an electrical supply circuit with capacitor(s) connected to the electric power source, and adapted so as to supply the electronic components of the apparatus while the needle is being melted. In this way, while an electric current is established between the electrodes and the needle is being melted, all the intensity delivered by the electric power source can be provided to the electrodes, the secondary electronic circuit being supplied from the electrical energy previously stored in the electrical supply circuit with capacitor(s).
In practice, it is found that the apparatus according to the invention is extremely simple, efficient and is not bulky (its typical dimensions being 170 mmxc3x9770 mmxc3x9743 mm); is light (less than 550 g); has considerable electrical autonomy enabling more than 80 needles of a diameter of 0.6 mm to be destroyed between recharges; may be constructed at low cost; has a long life; is particularly ergonomic, simple to use and maintain; and it enables each of the needles to be entirely destroyed after use without leaving any residual portion projecting from the syringe end piece or any dangerous sharp, contaminated residue. It is thus possible to consider equipping all the personnel of the health services and/or patients with an apparatus according to the invention.
The invention also concerns a process and an apparatus characterized in combination by all or part of the characteristics mentioned above or hereinafter.